1. Field of the Invention
This invention is related to measurement devices, and in particular to devices for measuring wear experienced by padeyes, shackles, chains, and other similar elements used in maritime applications and on-shore installations.
2. Description of the Related Art
In maritime industry, fastening devices are used that are typically fabricated of metal; that is, metal elements with rings and/or hooks. Such fastening devices are attached to, and secure other fastening devices and/or portions of ships, barges and boats, for maritime applications using anchors, moorings, and the like for securing a ship to a dock or other facilities. Such fastening devices experience wear from frictional interaction between adjacent and/or abutting portions of the fastening devices, as well as, other eroding or corroding factors and sources such as oxidation, interaction with salt water, pollution, cleaning chemicals, etc. For example, the wear of padeyes, shackles, and chains has caused problems in the past including the loss of anchor leg moorings in ship berths. Accordingly, repairs and maintenance of ship berths, dry-docks, anchorages and other facilities employing these marine restraining devices must be continually assessed and addressed.
Because of such wear, erosion, and/or corrosion, potential damage and even the loss of berthed ships, as well as pollution and/or damage to adjacent facilities from break-away vessels, can be the cause of potentially high costs and severe safety breaches. Necessary repairs and maintenance, as well as preventative measures, such as the temporary shutting down of critical facilities to undertake necessary, albeit costly, repairs, can result in severe economic damages and losses.
To minimize such costs, the regular inspection and replacement of worn fastening devices are essential. However, it has been found difficult to evaluate the degree of wear on such fastening devices, due to the inability of known devices to take reliable and accurate wear measurements.
The measurement devices of the prior art have not been able to provide reliable and accurate measurements. Thus, the appropriate assessment of wear of ship fastening devices has been frustrated due to, for example, the lack of visibility of the wear or the lack of reference surfaces for talking measurements. For example, reference surfaces can be inaccessible or out of a common plane with each other.
Using known measurement devices, the curved surfaces of such fastening devices prevent accurate measurements. Also, the portions of the fastening devices can be underwater without the opportunity to remove these devices out of the water, and so measurements may be unreliable due to poor visibility as well as the light-refraction effects of the surrounding water to gauge distances between components and portions of the fastening devices being measured.
In addition, ship fastening devices, whether on-shore or subsea often pose difficult problems in measurements by having a combination of a lack of visibility to the worn portions, a lack of accessible reference surfaces, and out-of-plane reference surfaces, being curved or being underwater.
In another example, direct visual assessment of wear between interconnected padeyes and shackles is made more difficult because the wear surfaces are typically hidden behind the shackle body.
Accordingly, a need exists for a reliable and accurate device for measuring the wear of chains, shackles, padeyes, and other fastening devices used in maritime applications, such as anchor legs.
It is therefore a principal object of the present invention to provide a reliable, easy to use and rugged tool for accurately measuring wear on the surfaces of chains and other fasteners in which the worn surfaces are out-of-plane.